PerimeterX secures $43M to protect web apps from bot attacks

We know by now that modern website attacks are typically automated, as armies of bots knock on doors until they inevitably find vulnerabilities and take advantage. PerimeterX, a San Francisco, startup wants to protect sites from these automated assaults. Today, it announced a $43 million Series C.

The round was led by Scale Venture Partners . New investor Adams Street Partners joined existing investors Canaan Partners, Vertex Ventures (which also invested via its new growth fund) and Data Collective in the round. Ariel Tseitlin, a partner at Scale, will be joining the company’s board under the terms of the deal. Today’s investment brings the total raised to more than $77 million, according to Crunchbase data.

Omri Iluz, co-founder and CEO at PerimeterX, says bots have become the preferred way of hackers to attack websites and mobile apps, and his company has developed a way to defend against that kind of approach. It uses an approach called behavioral fingerprinting to blunt these automated attacks.

“Once we gain visibility into the behavior of the user, we are able to discern between normal behavior and an anomalous behavior that looks like it’s coming from an automated tool,” he said. The solution looks at attributes like mouse movements and swipes. It also analyzes the hardware to understand the graphics driver and audio driver of whatever device the bot is purporting to be.

To achieve this kind of identification requires massive amounts of data, and PerimeterX uses machine learning to help understand normal behavior and shut down anomalous behavior in an automated fashion.

The company was founded in 2014 and currently has 140 employees. Ariel Tseitlin from Scale Venture Partners, whose firm is leading the round, says as companies reach this level of maturity, the Series C money tends to go into sales and marketing to push the revenue pedal and scale the company.

“While there is a lot of opportunity in R&D, generally at this stage most of the dollars are going for sales and marketing, so hiring more salespeople, hiring more marketers more sales ops. That’s where a big part of the expansion comes from, and that tends to be pretty closely correlated to revenue growth, and pretty closely correlated to just greater growth in general,” Tseitlin explained

We wrote about Signal Sciences’ funding last week, a company that also works to protect web apps using a firewall approach. Iluz says the two companies often work together with the same customers, rather than competing, because they attack the problem differently.

Note: The original version of this article has been updated to reflect that Vertex Ventures invested via its new growth fund.